Instant messaging (IM) is a set of communication technologies used for text-based communication between two or more participants over the Internet or other types of networks. IM-chat happens in real-time. Of importance is that online chat and instant messaging differ from other technologies such as email due to the perceived quasi-synchrony of the communications by the users. IM allows effective and efficient communication, allowing immediate receipt of acknowledgment or reply.
As IM is getting more popular, more often users have become targets of unsolicited spam and more unwanted messages may be received from unknown or unwanted sources. There has been a lack of sufficient spam filtering techniques available to counter the unwanted instant messages.